Yielding drive mechanism.



W. L. HUDSON.

YIELDING DRIVE MECHANISM. APPLICATION man MAR. 3. 1915.

1,182,486. 7 Patented May 9,1916.

wInLIAML, HUDSON, or nLLIsBuR-e, NE YORK.

YIELDING DRIVE MECHANISM.

- Specification of Letters Patent.

iPatented May 2, 121 6.

Application filed March 3, 1915. Serial No. 11,833.

To all whom itmay concern: I p v Be it known that I, lVILLIAM L. Hnnson,a citizen of the United States, andresident of Ellisburg, inthe countyof Jefferson and State of New York, have invented certain new and usefulImprovements in Yielding Drive Mechanism, of which'the following is aspecification. e a I This invention relates particularly to a drivemechanism such as is used in motionpicture machines, either those inwhich a film-strip is exposed, as ,ina camera, or those in whichpictures are projected from a film-strip. v

In connection with the take-up reel of a motion-picture machine it isnecessary to employ means for frotating the. reel con- ,stantly, and inorder to insure that the rotation shall be sufficient to maintain thefilm under sufficient tension, while at thesame time compensation shallbe made for the varying diameter of the roll of film on the reel, it isdesirable to employ frictional yielding connections between the reel andthe mechanism by whichit isrotated.

The object of the present invention is to provide simple and effectivefrictional connections between these parts and to provide for aconvenient adjustment of the degree,

of friction in these connections, and the invention resides inthe novelconstruction for that purpose hereinafter described.

In the acompanying drawings :-Figure 1 is a side-elevation of a portionof a motion picture projecting machine-embodying the present invention,with parts shown in section; Fig. 2 is a view, on a larger scale, of theadjustable frictional connections between the driving-pulley and theshaft of the take-up reel, shown from the inner side of the pulley; andFig. 3 is a sectional view on the line 3-3 in Fig. 2.

Theinvention is illustrated as embodied in a machine in which thefilm-strip 10 is guided and fed downwardly between two verticalguide-plates 11 and 12, the feeding movement being produced by pivotedfeeddogs 13 which engage the perforations in the margins of the film, ina well-known manner. The feed-dogs are reciprocated by mechanismincluding a pitman lfiroperated by a crank-pin on a disk 17 at the endof a shaft 18 which is geared to the power-shaft 19 of the machine. Thispower-shaft is provided with a pulley 20 which is connected, by a belt21, with a pulley. 22 connected with the shaft 23 by whichthetakeup reel14 is supported and rotated, and accordingly the reel is rotatedconstantly whenthe feed-mechanism is in operation. I The film, afterpassingdownwardly between the guide-plates 11 and 12, passes beneath afixed guide or abutment 25 which cylindrical in formand of a sufficientdi- .ameter to preventthe film from being bent to a sharp angle inpassing around it. From rection, to and over a similar fixed guide 26,and from the'latter it passes through the wall of the casing 15, betweenguide-rollers 2 1, and to the reel 14. Since the reel tends .mittentlyby the feed-mechanism, it will be apparent that atconstantlyrecurringinter vals a certainamount of slack film willibepresent between these instrumentalities. By means of the fixed guides 25and 26, however, I dispose effectively of this slack film, while at thesame time maintaining sufiicient tension on the film, as it is woundupon the take-up reel, to cause it to be wound closely. Owing to theresiliency of the film itself it tends, whenever slackened, to assume asmoothly curved form in those parts of it which, as shown in Fig. 1,extend straight between the guide-plates 11 and 12 and the guide 25, andbetween the latter and the guide 26. Accordingly, at each operation ofthe feed-mechanism the film which is de taken up by the reel isabsorbed, so to speak,

the guide 25 the film passes, in a reverse diby this change'in thedisposition of the film from a straight course to a curved course, andat the same time the slight friction of the film against the guides 25and 26 is sufiicient to cause the slackness from passing freely aroundthe guides and loosening the portion of the film which stretches betweenthe guide 26 and the reel to such an extent as to permit the film whichhas already been wound from loosening upon thereel.

Since it is necessary, in order to insure close winding of the film,that there be a tendency to drive the reel always somewhat faster thanis absolutely necessary to take up the film as delivered by thefeed-mechanism, I have so proportioned the gearing and the drivepulleysas to tend to drive the reel at the maximum speed necessary, and haveinterposed yielding connections between the drive-pulley 22 and theshaft 23 to accommodate the'surplus movement of the driving-mechanism asthe diameter of the roll increases. These connections are shown in Figs.2 and 3. The pulley 22 is journaled loosely upon the shaft 23 and heldthereon by a collar 27. The rim of the pulley is provided, on theinside, with sockets 28 which receive the ends of two leaf-springs 29.and 30, between which the shaft 23 is clasped, the resiliency of thesprings causing them to grip the shaft with a certain amount offriction, so. that'when the pulley is rotated it tends to rotate theshaft also, but with a degree of force which is insufficient to causeinjury to the film or the mechanism when the pulley rotates faster thanbears against the spring 29, and by turning the eccentric the spring maybe forced with more or less pressure against the shaft 23, thus varyingthe degree offriction by which thepulley and the shaft are coupledtogether. The eccentric is retained in its adjusted position by thefriction'between it and the spring.

My invention is not limited to the embodiment thereof hereinbefore'described and illustrated in the accompanying drawings, but it may be.embodied in various other forms within the nature of the invention asit is defined in the following claims.

l. The combination, with a drive-shaft, of a pulley mounted on androtatable with respect to the drive-shaft, and a pair of leaf-springssupported, at their ends, upon the pulley and between which said shaftis frictionally clasped.

2. The combination, with a drive-shaft, of a pulley mounted on'androtatable with respect to the driveeshaft, a pair of leafspringssupported, at their ends, upon the pulley and between which said shaftis frictionally clasped, and adjustable means forregulating the pressureof one of said springs against the shaft.

3. The combination, with a drive-shaft, of

a pulley mounted'on and rotatable with respect to the drive-shaft, apair of leafsprings supported, at their ends, upon the pulley andbetween which said shaft is frictionally clasped, and aneccentriccarried by the pulley and engaging one of said leaf springs, theeccentric being rotatable to force said spring with a variable pressureagainst said shaft.

In testimony whereof, I aflix my signature in presence of two witnesses.

WILLIAM L. HUDSON.

Witnesses: V

'B. S. BEEBE, A. G. DAY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents.

Washington, D. 0.

